Internet telephone apparatus to communicate with an external device via the Internet is known. Internet telephone apparatus is made available by installing an Internet telephone program offered by an Internet telephone service provider on a personal computer (hereinafter, referred to as “PC”) connectable to the Internet. Examples of a known Internet telephone program include “SKYPE” (registered trademark) offered by Skype Technologies S.A.
The Internet telephone apparatus sends and receives packetized sound data to and from an external device in accordance with Internet Protocol (hereinafter, referred to as “IP”). Furthermore, Internet telephone apparatus has various functions which make full use of the characteristics of IP.
For example, the Internet telephone apparatus has a function of accepting a call received from an external device while the Internet telephone apparatus is performing communication with another external device (interrupt function) by taking the advantage that the Internet telephone apparatus can exchange data with two or more devices at the same time. Even during communication with an external device, by using the interrupt function, the Internet telephone apparatus can accept a call by closing the line when the call is received from another external device.
The interrupt function is implemented by a server installed by the Internet telephone service provider, or by the Internet telephone program installed on the PC.